Yes, these are global stats, but as someone from the third world myself, I can say that most gamers around here resort to piracy, even though steam has gained a lot of popularity, so, only a fraction of us are included in the steam statistics, which would make such data not very representative.

Perhaps a better source for understanding software usage in the third world is data from statcounter. They show something around 3 to 5%, a much higher number. However, even this data can be biased, because they only count machines connected to the internet and who browse certain sites.

Good question, almost all of my country's government PCs are still running Windows 7.

Yes... It's anyone internet connected with steam, ie the people who this will affect